But the 26-year-old man is a native of Somalia. Because Somalia has no government, U.S. officials cannot deport people there. But officials also could not hold him after his release from federal custody in May 2010, following an assault conviction. Generally, officials are prohibited from detaining criminal aliens longer than six months after their release from custody.

So the man, who once lived in the Twin Cities and who recently had been splitting time between Minot and the oil fields of Williston, N.D., was on supervised release when the mother of his child and three others were killed last week.

The Star Tribune is not naming the man, who has not been arrested or charged in connection to the killings. Police have not said he is a suspect in the slayings. He was being held Thursday in the Grand Forks County jail at the direction of U.S. Immigration and Customs Enforcement.

ICE spokesman Shawn Neudauer confirmed that the man is being held for violating the conditions of his supervised release, but he could not say what the man did to violate those conditions. Neudauer also said he did not know what officials did after losing contact with the man. ICE arrested him Tuesday, and he was held at the Ward County jail in Minot until ICE moved him to Grand Forks on Wednesday.

The killings

Police found 19-year-old Sabrina Zephier, the mother of the man's 5-month-old daughter, dead Friday. Their baby was found alive in the apartment.

Killed an hour later were Zephier's mother, Jolene Zephier, 38; Sabrina Zephier's brother, Dillon Zephier, 13, and Jolene Zephier's boyfriend, Jeremy Longie, 22. Police found their bodies in Jolene Zephier's mobile home. All four were shot, Minot police Capt. Dan Strandberg said.

Minot Police Chief Jeff Balentine said on Thursday that the man has been interviewed as a "person of interest" in the case. No charges have been filed.

Autopsy results have yet to be released. Authorities have not commented on a motive behind the killings.

Under usual circumstances involving an immigrant with a violent criminal record, the man -- suspect or not -- would probably not have been in the United States when the killings happened.

He has an extensive criminal record in Minnesota. His most serious offense occurred in January 2006, when he stabbed another male during an altercation in an apartment building entry near Cedar and Riverside Avenues in Minneapolis.

According to the charges, several others were involved in that assault, which left the victim with a collapsed lung, a concussion and stab wounds to his right eye, right shoulder and back.

In June 2006, the man pleaded guilty in Hennepin County to second-degree assault with a dangerous weapon, a felony. He was sentenced to one year and one day in prison with credit for 143 days served. He finished his state prison term in January 2007.

It is the practice of immigration officials to begin deportation proceedings immediately after an alien offender is released from local or state custody. But that gets dicier when dealing with offenders from countries that either refuse to take them back or do not have formal relations with the United States.

Somalis can still be under deportation orders, but those orders are not acted upon.

When asked whether officials obtained a deportation order regarding the man, immigration officials referred to a June 2001 ruling by the U.S. Supreme Court.

In that ruling, a Lithuanian man with a long criminal record who had been ordered deported could not be deported because no country would accept him. Yet, the high court ruled, U.S. officials could also not keep him locked up indefinitely. Generally, the court ruled, such offenders cannot be detained for more than six months